Chlorate candle and method of making same

ABSTRACT

A method of manufacturing an oxygen generating chlorate candle including the steps of forming a powder-like candle mixture, supplying the mixture to a cavity, closing the cavity, reducing the dimensions of the cavity by a horizontal pressing operation to form the candle, increasing the dimension of the cavity to release the formed candle from at least some of the side walls of the cavity and removing the candle from the cavity.

United States Patent Thompson 1 Oct. 21, 1975 [54] CHLORATE CANDLE ANDMETHOD OF 3,097,057 7/1963 Takeuchi 264/325 X MAKING SAME 3,366,3681/1968 Hibbing 264/120 X 3,555,730 l/1971 Brink 425/352 lnventorl TommyLewls Thompson, 3,720,491 3/1973 Dedek 425/353 x Melbourne, Fla. [73]Assignee: Life Support, Inc., Melbourne, Fla. Primary xaminer-Robe t F.Stahl Assistant Examinea-Harold Tudor [22] Sept 197.3 Attorney, Agent,or Firm-Hill, Gross, Simpson, Van [21] Appl. N0.: 394,689 Santen,Steadman, Chiara & Simpson 52] US. Cl 264/3 R; 23/281; 264/325 [57]ABSTRACT 5 3 5 2 A method of manufacturing an oxygen generating v z g112 5, chlorate candle including the steps of forming a pow- 1 23/2r 2der-like candle mixture, supplying the mixture to a cavity, closing thecavity, reducing the dimensions of the cavity by a horizontal pressingoperation to form [56] References and the candle, increasing thedimension of the cavity to UNITED STATES PATENTS release the formedcandle from at least some of the 549,274 11/1895 Mellen.....; 425/354side walls of the cavity and removing the candle from 1,575,300 3/1926Weeks et al. 264/320 X th it 2,983,588 5/1961 Bovard 23/281 3,096,2487/1963 Rudzki 264/112 2 Claims, 9 Drawing Figures US. Patent Oct.2319751 Sheet1of2 3,914,355

U.S. Patent Oct. 21, 1975 Sheet20f2 3,914,355

CHLORATE CANDLE AND METHOD OF MAKING SAME BACKGROUND OF THE INVENTION 1.Field of the Invention This invention relates to chemical oxygengenerator cells and to a method of forming the oxygen producing candleportion of the cell by a pressing operation.

2. Description of the Prior Art Chemical oxygen generating devices areknown which incorporate a housing such as a tin plated can which hasdisposed therein an oxygen producing candle. See for example U.S. Pat.No. 3,736,104 for an ox ygen generator cell issued May 29, 1973 to JohnP. Churchill and Tommy Lewis Thompson, the teachings of which are hereinincorporated by reference.

Such cells generally contain a compressed chlorate candle briquette,preferably of the chemical formulation disclosed and claimed in my U.S.Pat. No. 3,702,305, issued Nov. 7, 1972. The briquette generallyincludes an ignition material cone set in one end of the briquette forinitiating buring of the chlorate candle. The material for such cones isdisclosed in my U.S. Pat. No. 3,725,156 issued Apr. 3, 1973. Theteachings of these patents are herein incorporated by reference.

Although the prior art has generally constructed the candle as acylindrical mass with the ignition cone attached to or impressed in oneend of the cylinder, other shapes have been suggested such as, by way ofexample, frustoconical. Recently, it has been determined that in orderto assure a steady and even rate of oxygen delivery while minimizingheat loss, more complex shapes are required. Such a shape is illustratedin my Patent Application entitled Oxygen Generator Cell, U.S. Ser. No.338,448, filed Mar. 6, 1973, the teachings of which are hereinincorporated by reference.

The formation of such candles generally begins with the creation of amixture of the candle material. This material is then formed into thedesired shape. The prior art has suggested that the candle can befabricated by casting, hot compression molding, hot extrusion, orhydrostatic compaction. While modifications of such standard techniquescan be utilized in the formation of candles, the majority of thesuggested methods, with the exception of compression molding, have thedisadvantages of either being unable to produce the complex shapedcandles which have been found to be the most advantageous or, theyinvolve expensive procedures not readily usable for the economical massproduction of inexpensive, disposable oxygen supplying equipment.

Compression molding, on the other hand, has the advantage of being bothfast and inexpensive. Normally, such compression molding involves theuse of a shaped cavity and a vertical ram which compresses the materialinto the shaped cavity. Such systems are not usable with the complexconfigurations of the above discussed new candle shapes inasmuch as itwould be impossible to remove the compressed candles from the cavity.

Horizontal pressing has been suggested. However, the suggested forms ofhorizontal pressing have merely utilized a dimensioned cavity having aram moving horizontally therein to compress material received in thecavity. While this increases the ability to create complex forms and toremove the resultant candles from the mold, such systems still requireejection devices and are not readily usable on high volume productionlines. In addition, they have the disadvantage of limiting theability-of the ignition cone to be formed into the candle at the timethe candle is pressed.

It would therefore be an advance in the art if a high volume,inexpensive production method could be devised for the manufactureofcomplex shaped oxygen generating candles. It would be a further advancein the art if such a method could include a means for affixing theignition cone to the candle at the time of formation of the candle.

SUMMARY My herein disclosed invention provides such a solution. In thepreferred embodiment illustrated, my method includes the use of ahorizontal pressing device having a cavity formed between two stationaryside walls and twov movable side walls, the cavity being open at bothvertical ends. Means are provided to close the vertical openings of thecavity.

In the construction of an oxygen generating candle, I began with amixture of materials for the formation of the candle. This mixturepreferably is in granulated, powdered, or slurry form and is introducedto the cavity through the top opening. The bottom opening is closed atthetime of introduction of the material. The material is introduced tothe cavity to a level slightly below the top of the cavity as defined bythe bottom of the top slide. Thereafter, a pre-formed ignition cone isplaced in the candle mixture. The top slide is activated to close thetop of the cavity and the movable side walls are activated in unison tomove the cavity to a point spaced from the slides. Thereafter, the sidewalls are moved towards one another to reduce the size of the cavitythereby compressing the candle into final shape. Thereafter, the movableside walls are returned to their initial position above the bottomopening and the bottom slide is moved to allow the resultant candle toexit from the cavity.

Such a compression device and method results in the formation of a highquality compressed candle with the ignition cone properly placed.

It is therefore an object of this invention to provide a method ofmanufacturing oxygen generating candles.

It is another and more specific object of this invention to provide amethod of producing complex shaped oxygen generating candles bycompression molding.

It is another and more important object of this invention to provide amethod and apparatus for the production of chlorate candles bycompression molding in a die cavity from a candle mixture introduced tothe cavity in a loose state.

It is another and more important object of this invention to provide amethod and apparatus for the production of chlorate candles withignition cones embedded therein, the ignition cone being embedded in thechlorate candle when the chlorate candle is formed to a final shape in acompression molding process.

It is yet another and more specific object of this invention to providea method and apparatus for the formation of oxygen producing chloratecandles with embedded igniter cones with involves the steps of fillingan oversized die cavity formed between movable walls and stationarywalls with a candle mixture, placing an igniter cone in the mixture,closing the cavity, reducing the dimension of the cavity to a finalcandle size dimension, increasing the size of the cavity and ejectingthe formed candle therefrom.

Other objects, features, and advantages of the present invention will bereadily apparent from the following description of the preferredembodiments thereof taken in conjunction with the accompanying drawingsalthough variations and modifications may be effected without departingfrom the spirit and scope of the novel concept of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective partiallysectional view of an oxygen generator cell.

FIG. 2 is a perspective view of an oxygen generating candle formedaccording to this invention.

FIG. 3 is a diagrammatic view, partially in section, of a cavity fillingstep according to the method and utilizing the apparatus of thisinvention.

FIG. 4 is a cross-sectional view taken along lines IV-IV of theapparatus of FIG. 3.

FIGS. 5, 6, 7, and 8 are views similar to FIG. 3 illustrating successivesequential steps in the practice of this invention.

FIG. 9 is a cross-sectional view of the finished candle taken along thelines IXIX of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates an oxygengenerating cell 10 as shown and described in my prior US. Pat.Application entitled Oxygen Generator Cell, U.S. Ser. No. 338,458, filedMar. 6, 1973. The cell includes a cylindrical tin can 11 with top 13 andbottom 14 walls. The top wall 13 has a circular central opening 15closed by a foil strip 16. An ignition actuator cup 17 depends from thetop 13 below the opening 15 and is closed by another foil strip 16b.Below the top and surrounding the ignition actuator cup 17 are discs ofceramic fiber material 18, ceramic fiber mat l9 and a layer of granularsodium peroxide 20. A further ceramic fiber mat 21 underlies thegranular layer 20. A tin plated steel baffle 22 underlies the disc 21and has a pair of diametrically opposed flat legs 24 depending from theend wall 23 of the baffle and terminating in close space relation to thebottom of the can where it may be supported on a mat 25. The portion 23of the baffle has a central opening 26 which receives a reduced diameterportion of the cup 17. Under the portion 23 0f the baffle may bepositioned a plurality of mats 27, some of which surround the cup 17 andsome of which surround a pellet of first fire material 30 which ispositioned atop a central portion of a sodium chlorate candle 31 whichhas an end face 32 positioned immediately below the lowest mat 27 andthe first fire material 30. An igniter cone 33 is impressed into the end32 of the candle 31.

A plunger pin 35 is recieved in the cup 17 which may be filled with anigniter fluid such as water. Activation of the plunger pin 35 willpierce the end 36 of the cup 17 and will force the fluid into the firstfire material 30 which will initiate activation of the igniter cone 33and the sodium chlorate candle 31.

As illustrated in FIG. 2 the sodium chlorate candle 31 is a compressedbriquette which is formed of a material which will maintain aselfsustaining catalytic decomposition reaction which will liberateoxygen from the material without the addition of additional heat orfuel. The shape of the candle is as disclosed in my aforementionedpatent application Ser. No. 338,458, filed Mar. 6, 1973 and has a mainelongated hexagonal cross section body portion 40 which convergesthrough a tapered portion 41 to abouta halfway point between the topandbottom ends of the briquette and from this level adjoining faces ondiagonal opposite sides of the hexagon are cut back in triangular flats43 to terminate in a rectangular base 44 which rests on the mat 25.

The briquette is formed from a formulation such as that set forth in myaforesaid US. Pat. No. 3,702,305 which is preferably initially preparedas a powder, granular mixture, or slurry, hereinafter referred to as apowder. The powder mixture must be compressed under high pressure toform the briquette and, it is desirable, that the pressure besubstantially uniform in all sections of the briquette to provide acompacted finished product which will burn evenly to release acontinuous amount of oxygen. Of course it is to be understood that otherconfigurations can be created where it is desired, for example, toinitially produce a high flow rate of oxygen which thereafter tapers toa lesser rate or vice versa.

According to this invention the briquette 3] is formed by horizontalpressing. It is to be understood that the term horizontal pressing isherein used to refer to pressing from the long sides of the briquette asopposed to pressing from the top and/or bottom ends of the briquette.

As best shown in FIGS. 3 and 4, the pressing is done in a pressapparatus which includes movable rams and 51 disposed opposite oneanother. The rams are received between top and bottom chamber definingmembers 52 and 53 each of which has an opening 54 and 55 therethrough.The openings 54 and 55 are closable by top and bottom slide members 56and 57. Side walls 58 and 59 close the area to either side of the rams50 and 51. Therefore, when the rams are spaced apart as illustrated inFIG. 3 a chamber 60 is defined between the opposed surfaces 61 of ram 51and 62 of ram 50, the inside surfaces 63 of side wall 58 and 64 of sidewall 59 and the combination of the members 52 and 53 and the slides 56and 57. It will be understood that the rams are movable and are actedupon mechanically or hydraulically and that the slides are also movableand are actuated by external motive means.

The top portions of the side of the rams 50 and 41 may be angledinwardly with corresponding angulations of the side walls 58 and 59 andthe side faces 61 and 62 of the rams 50 and 51 may be configured withangled top and bottom portions so as to provide the final briquetteshape as illustrated in FIG. 2 or some other desired shape.

The rams 50 and 51 are independently movable towards and away from oneanother and are initially positionable such that the cavity 60 underliesthe opening 54 and overlies the opening 55. Because the rams areindividually movable, the initial cavity 60a as illustrated in FIG. 3can be formed oversized with respect to the final briquette size.

The powder mixture 70 is introduced to the cavity 60a through theopening 54 with the slide 57 closed. It will be noted that in theembodiment illustrated the top surface 71 of the slide 57 and the bottomsurface 72 of the slide 56 are level with the corresponding surfaces ofthe members 52 and 53 which are continuous except for the slides'and theopenings 54 and 55. The powder material is introduced to the cavity to alevel below the bottom surface 72 of the slide 56 while the rams 50 and51 are spaced apart from one another a distance such that the totalamount of powder material introduced to the oversized cavity 60a isequal to the'desired weight of powderin the finished briquette.Thereafter, as illustrated in FIG. 5, the ignition cone 33 is placed inthe powder 70 through the opening 54; The ignition cone may be placed byany means such Eas by hand or automated machinery or theIike'and ispressed into the powder.,so.thattthe top 33a of the cone'lies below thebottom-surface 72-"of the. slide-56. Thereafter, as illustrated in FIG,6, the slide 56 is-closed closing the opening'54 and the rams 50andSLare moved to one side of the openings;54 andSS where the cavity 6013will be defined between the ,opposed faces of the rains 50 and 51 andthe opposed surfaces of the members 52 and 53 and the opposedfaces ofthe side walls 58 and 59. It is to be understood that this movement ofthe rams is an equal movement where both rams move the same distancemaintaining the cavity60b at substantially the same size asthe cavity60a with the top. closed. Further, it will be understood that movementof the rams is in a preferred embodiment only and that in otherembodiments, the slides 56 and 57 could be constructed of a sufficientlyheavy material to withstand the pressures generated during the pressingoperation. In such an instance then the pressing can ,take place,between the rams in the area under the slides and in alignment with theopenings 54 and 55. Y K t;

As illustrated in FIG. 7 after themovement illustrated in FIG. 6, therams are moved towards one another to reduce the cavity 60b to a finalbriquette size 60c compressing the powder material70 to ,the desireddensity. It will be appreciated that the ignition cone 33 will bemaintained in' the center portion of the briquette by the pressuregenerated by the ram and willbe firmly embedded in the briquette duringthe pressure formation of the briquette. Further, because of the coneshape, the ignition cone 33 will remain at the top of the finalbriquette.

Although in the preferred embodiment the rams 50 and 51 cooperate bymoving towards one another to form the briquette, in other embodimentsone of the rams could remain stationary during the pressing operationwhile the other ram moves toward it to reduce the cavity to the size60c.

Thereafter, the rams are moved in unison to a position above the opening55. At this point as illustrated in FIG. 8, the rams are separated fromone another to create a cavity 60d which is larger than the briquette31, thereby releasing the briquette from at least one ram wall, anyadhesion to the side walls or members 52 central portion as illustratedin FIG. 9 while still maintaining a proper density.

' Thus, my invention envisions the use of opposed movable rams which arereceived between stationary side wall portions to create a four walledcavity with two of the opposed walls'defined by opposed faces of theram'sQThe cavity has top and bottom walls formed either by the movableslides 56 and 57 or by the stationary surfaces of the members 52 and 53to one side of the openings 54 and 55. The dimensions of a cavity formedbetween the ram faces are changeable by movement of the rams, In thepreferred embodiment, both rams are movable to allow the cavity to beshifted to the area underlying the members 52 and 53 spaced to the sideof the opening and to ensure that the briqutte will beweasily removablefrom the cavity when it is in finished. form. In an alternativeembodiment, the apparatus may form the final briquette by compressingthe material in a cavity area intermediate the openings 54 and 55 whichis closed by heavy slides 56 and 57. In other embodiments, the openings54 and 55may be offset from one another with the pressing being done inalignment with one or the other opening which may be closed .by a heavyslide or in an area intermediate the openings;

sequentially, my method comprises the steps of forming a cavity havingan opening thereto, thecavity having a first dimension and location,supplying a measured quantity of powder mixture to the cavity throughthe opening, inserting an ignition cone into the cavity through theopening at the top of the powder mixture,

, closing the opening to the cavity, shifting the cavity to and 53beingbroken by movement of the cavity 600 to t the position above theopening 55. In this manner, when the slide 57 is moved to open theopening 55, the briquette 31 will fall from the cavity 60d.

As the briquette 31 is removed from the pressing apparatus, it will beformed into the final desired shape as illustrated in FIG. 2, by reasonof having been pressed against the side walls 63, 64, the top and bottomsurfaces of the members 52 and 53 and the opposed faces of the rams. Byforming the triangular shaped portions 43 of the briquette by theopposed faces of the rams,

and thereafter by separating the rams as illustrated in FIG. 8, it isassured that the final shaped briquette can be removed through theopening 55.

It will be appreciated that because the initial cavity 600 issubstantially larger than the finished briquette,

the finished briquette can be made with the hexagonal a location spacedfrom the first location, reducing the size of the cavity to a seconddimension less than the first dimension to compress the powder materialto a finished formed briquette, shifting the cavity back to the firstposition, increasing the size of the cavity from the second dimensionand opening the cavity to eject the finished briquette with embeddedignition cone. Of course, it will be understood that the shifting of thecavity can be eliminated when using the embodiment with the heavierslides 56 and 57.

Although minor modifications might be suggested by those versed in theart, it should be understood that I wish to employ within the scope ofthe patent warranted herein all such modifications as reasonably andproperly come within the scope of my contribution to the art.

I claim as my invention:

1. The method of manufacturing a compressed oxygen producing candle byhorizontal compression molding in a fixture which comprises steps of:

5 providing a fixture with top, bottom and two opposed ings, the cavityhaving a first size and being located at a first position aligned withthe top opening;

positioning the bottom closure in a bottom opening closed position,

another, and the second walls being spaced from one another deferring acavity between the side and second walls, the opposed surfaces of thesecond walls being contoured to provide nonpositioning the top slide inan open position with the continuously planar di Surfaces,

P Qpeningfiommunicflting with the Cavity, providing top and bottomopenings through fixture l l fiytg i the g a gowder materigl portionsconnecting the side walls above and below t mug e P p g W 16 W Q P F thesecond walls, the openings communicating to fg Tigge g tig iyvkgf t kngz gi ihg igg i said cavity defined by said walls, slide closures atpartially submerging the ignition cone in the pow -Sald top and one"?openings for closmgsaid opender metal moving the top slide to a closedposition the cavl-t havltlg a slze and bemg lfmated at a first positionaligned with the top opening;

closmg the top Opening shifting the cavity to a positioning the bottomclosure in a bottom opening ond cavity position remote from the firstcavity po- 61 use d position sition and remote from the top and bottomopen- 5 h rd th ings by horizontal movement of the second walls,posltlonmgt 6 top SI posl I e reducing the size of the cavity to asecond size less top qpemng.commumc?nng.wlth the cavlty pthan the firstsize while compressing the powder Stanuany finmg the a powder materialmaterial to form a compressed candle with an ignithrough the topopening. which when 9 i tion cone embedded in the candle at the topffmns an ofqgen l candle placmg an g thereof by horizontal movement ofthe second uon,cone m the E f i the P opemng walls, increasing thecavity to a third size larger Pamauy submefgmg the lgnimon cone m the PQthan the second size and shifting the cavity back to def m movmg topSl'de a close'd posmon the first position by horizontal movement of thethe top opeflmgr reducmg the of h Second walls, moving the bottom Slideto an open cavity to a second size less than the first size whileposition communicating the bottom opening with the cavity, and removingthe compressed candle from the cavity through the bottom openings.

compressing the powder material to form a compressed candle with anignition cone embedded in the candle at the top thereof by horizontalmovement of the second walls, increasing the cavity to a third sizelarger than the second size, moving the bottom slide to an open positioncommunicating the bottom opening with the cavity, and removing thecompressed candle from the cavity through the bottom openings.

2. The method of manufacturing a compressed oxygen producing candle byhorizontal compression molding in a fixture which comprises steps of:

providing a fixture with top, bottom and two opposed stationary sidewalls, and two opposed horizontally movable second walls positionedbetween the stationary walls, the side walls being spaced from one

1. THE METHOD OF MANUFACTURING A COMPRESSED OXYGEN PRODUCING CANDLE BYHORIZONTAL COMPRESSION MOLDING IN A FIXTURE WHICH COMPRISES STEPS OF:PROVIDING A FIXTURE WITH TOP, BOTTOM AND TWO OPPOSED STATIONARY SIDEWALLS, AND TWO OPPOSED HORIZONTALLY MOVABLE SECOND WALLS POSITIONEDBETWEEN THE STATIONARY WALLS, THE SIDE WALLS BEING SPACED FROM ONEANOTHER, AND THE SECOND WALLS BEING SPACED FROM ONE ANOTHER DEFERRING ACAVITY BETWEEN THE SIDE AND SECND WALLS, THE OPPOSED SURFACES OF THESECOND WALLS BEING CONTOURED TO PROVIDE NON-CONTINUOUSLY PLANAR DIESURFACES, PROVIDING TOP AND BOTTOM OPENINGS THROUGH FIXTURE PORTIONSCONNECTING THE SIDE WALLS ABOVE AND BELOW THE SECOND WALLS, THE OPENINGCOMMUNICATING TO SAID CAVITY DEFINED BY SAID WALLS, SLIDE CLOSURES ATSAID TOP AND BOTTOM OPENINGS FOR CLOSING SAID OPENINGS, THE CAVITYHAVING A FIRST SIZE AND BEING LOCATED AT A FIRST POSITION ALIGNED WITHTHE TOP OPENING, POSITIONING THE BOTTOM CLOSURE IN A BOTTOM OPENINGCLOSED POSITION, POSITIONING THE TOP SLIDE IN AN OPEN POSITION WITH THETOP OPENING COMMUNCATING WITH THE CAVITY, SUBSTANTIALLY FILLING THECAVITY WITH A POWDER MATERIAL THROUGH THE TOP OPENING WHICH, WHENCOMPRESSED, FROM AN OXYGEN PRODUCING CANDLE, PLACING AN IGNITION CONE INTHE CAVITY, THROUGH THE TOP OPENING, PARTIALLY SUBMERGING THE IGNITION2. The method of manufacturing a compressed oxygen producing candle byhorizontal compression molding in a fixture which comprises steps of:providing a fixture with top, bottom and two opposed stationary sidewalls, and two opposed horizontally movable second walls positionedbetween the stationary walls, the side walls being spaced from oneanother, and the second walls being spaced from one another deferring acavity between the side and second walls, the opposed surfaces of thesecond walls being contoured to provide non-continuously planar diesurfaces, providing top and bottom openings through fixture portionsconnecting the side walls above and below the second walls, the openingscommunicating to said cavity defined by said walls, slide closures atsaid top and bottom openings for closing said openings, the cavityhaving a first size and being located at a firSt position aligned withthe top opening; positioning the bottom closure in a bottom openingclosed position, positioning the top slide in an open position with thetop opening communicating with the cavity, substantially filling thecavity with a powder material through the top opening which, whencompressed, forms an oxygen producing candle, placing an ignition conein the cavity, through the top opening, partially submerging theignition cone in the powder metal, moving the top slide to a closedposition closing the top opening, reducing the size of the cavity to asecond size less than the first size while compressing the powdermaterial to form a compressed candle with an ignition cone embedded inthe candle at the top thereof by horizontal movement of the secondwalls, increasing the cavity to a third size larger than the secondsize, moving the bottom slide to an open position communicating thebottom opening with the cavity, and removing the compressed candle fromthe cavity through the bottom openings.